The severity of human periodontal disease has been directly correlated to the serum copper concentration. A model system, using both rice rats and hamsters, and which utilizes graded, controlled-intake levels of dietary copper will be employed to evaluate the influence of this nutrient on the development of experimental periodontal disease. Hepatic copper mobilization and the activity of specific metalloenzymes, ceruloplasmin, lysyloxidase, superoxide dismutase and cytochrome oxidase will be correlated with dietary copper and periodontal lesions. The influence of dietary zinc, calcium and phosphorus will also be investigated. Copper metabolism in the oral tissues will be investigated in vivo and in vitro. The role of bacterial endotoxins, leukocytic endogenous mediator and antibiotics in the uptake and function of 67Cu and 67Cu-ceruloplasmin will be investigated in vitro using gingival tissues from normal animals and those exhibiting signs of periodontal disease. These experiments will attempt to define the role of copper in periodontal disease.